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我正在尝试使用 CryptoAPI 加密/解密单个缓冲区。

我已经成功地加密/解密密钥和导入/导出密钥 BLOB。我也（仅在表面意义上）成功地加密（仅）数据。

以下代码成功加密数据。解密时，它成功解密数据，但报告“NTE_BAD_DATA”。

标头中的全局变量：

HCRYPTPROV cryptprov;
HCRYPTKEY pubenckey;
HCRYPTKEY cryptprivkey;
LPVOID keystore;

创建会话密钥：

DWORD ret = 0;
ZeroMemory(&cryptprov,sizeof(cryptprov));
CString cwinver("Windows 7";);
string winver = cwinver.GetBuffer();
wstring provname;
wstring contname = L"Container";
if (winver.compare("Windows XP") == 0) { provname.assign(L"Microsoft Enhanced RSA and AES Cryptographic Provider (Prototype)"); } else { provname.assign(L"Microsoft Enhanced RSA and AES Cryptographic Provider"); }

ret = CryptAcquireContextW(&cryptprov,contname.c_str(),provname.c_str(),PROV_RSA_AES,CRYPT_SILENT);
if (ret == FALSE) { ret = CryptAcquireContextW(&cryptprov,contname.c_str(),provname.c_str(),PROV_RSA_AES,CRYPT_SILENT|CRYPT_NEWKEYSET); }
if (ret == FALSE) {
    return -1;
}
HCRYPTHASH hashobj;
CStringW cpass("testpass");
wstring pass = cpass.GetBuffer();
ret = CryptCreateHash(cryptprov,CALG_MD5,NULL,NULL,&hashobj);
if (ret == FALSE) {
    return -1;
}
ret = CryptHashData(hashobj,(LPBYTE)pass.c_str(),pass.size(),0);
if (ret == FALSE) {
    return -1;
}

ret = CryptDeriveKey(cryptprov,CALG_AES_256,hashobj,0x01000000|CRYPT_EXPORTABLE,&cryptprivkey);
if (ret == FALSE) {
    return -1;
}
CryptDestroyHash(hashobj);
return ret;

生成密钥，导出 blob，使用会话密钥对其进行加密，然后写入文件：

DWORD ret = 0;
int buflen;

ret = CryptGenKey(cryptprov,CALG_AES_256,0x01000000|CRYPT_EXPORTABLE,&pubenckey);
if (ret == FALSE) {
    return -1;
}
DWORD count;
ret = CryptExportKey(pubenckey,0,PLAINTEXTKEYBLOB,0,NULL,&count);
if (ret == FALSE) {
    return -1;
}
buflen = count + 100;
keystore = VirtualAlloc(NULL,buflen,MEM_COMMIT|MEM_RESERVE,PAGE_EXECUTE_READWRITE);
ret = CryptExportKey(pubenckey,0,PLAINTEXTKEYBLOB,0,(BYTE *)keystore,&count);
if (ret == FALSE) {
    return -1;
}
DWORD origkeyblocksize = count;
ret = CryptEncrypt(cryptprivkey,NULL,TRUE,0,NULL,&count,buflen);
if (ret == FALSE) {
    return -1;
}
ret = CryptEncrypt(cryptprivkey,NULL,TRUE,0,(BYTE *)keystore,&count,buflen);
if (ret == FALSE) {
    return -1;
}
memcpy((void *)((LONG)keystore+count),(void *)&origkeyblocksize,4);
string filen = "C:\\testenc.enc";
if (filen.compare("") != 0) {
    HANDLE fileh = CreateFile(filen.c_str(),GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE,NULL,CREATE_ALWAYS,FILE_ATTRIBUTE_NORMAL,NULL);
    if (fileh != INVALID_HANDLE_VALUE) {
        ret = WriteFile(fileh, keystore, count+4, &count, NULL);
    } else { ret = -1; }
    CloseHandle(fileh);
} else { ret = -1; }
if (ret != -1 && ret != FALSE) { ret = (LONG)keystore; }
return ret;

另一个应用程序读取文件并导入密钥：

DWORD ret = 0;
DWORD datalen;
DWORD bufsize = 0;
DWORD origkeysize = 0;

string filen = "c:\\testenc.enc";
if (filen.compare("") != 0) {
    HANDLE fileh = CreateFile(filen.c_str(),GENERIC_READ|GENERIC_WRITE,FILE_SHARE_READ|FILE_SHARE_WRITE,NULL,OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL,NULL);
    if (fileh != INVALID_HANDLE_VALUE) {
        DWORD fsize = GetFileSize(fileh,0);
        bufsize = fsize-4;
        keystore = VirtualAlloc(NULL,bufsize,MEM_COMMIT|MEM_RESERVE,PAGE_EXECUTE_READWRITE);
        ret = ReadFile(fileh, keystore, fsize-4, &datalen, NULL);
        ret = ReadFile(fileh, &origkeysize, 4, &datalen, NULL);
        CloseHandle(fileh);
        if (ret == FALSE) { ret = -1; }
    } else { ret = -1; }
} else { ret = -1; }
if (ret == FALSE || ret == -1) {
    return -1;
}
datalen = bufsize;
ret = CryptDecrypt(cryptprivkey,NULL,TRUE,0,(BYTE *)keystore,&datalen);
if (ret == FALSE) {
    return -1;
}
ret = CryptImportKey(cryptprov,(BYTE *)keystore,origkeysize,0,0,&pubenckey);
if (ret == FALSE) { ret = -1; } else { ret = (LONG)keystore; }
return ret;

缓冲区加密（缓冲区指针作为 LONG 传入，前 12 个字节用于加密/未加密数据长度）：

DWORD ret = 0;
DWORD buflen;
DWORD count;
memcpy((void *)&count,(void *)((LONG)passedbufferptr),4);
count-=12;

buflen = count + 32;
ret = CryptEncrypt(pubenckey,NULL,TRUE,0,NULL,&count,buflen);
if (ret == FALSE) {
    return -1;
}

ret = CryptEncrypt(pubenckey,NULL,TRUE,0,(BYTE *)((LONG)passedbufferptr+12),&count,buflen);
if (ret == FALSE) {
    return -1;
}
memcpy((void *)((LONG)passedbufferptr+8),(void *)&count,4);

return ret;

数据解密：

DWORD ret = 0;
DWORD count;
memcpy((void *)&count,(void *)((LONG)passedbufferptr+8),4);

ret = CryptDecrypt(pubenckey,NULL,TRUE,0,(BYTE *)((LONG)passedbufferptr+12),&count);
if (ret == FALSE) {
    return GetLastError();
}

return ret;

最后一个代码块始终返回 -2146893819 (NTE_BAD_DATA)。然而，在检查缓冲区时，它被解密。

需要注意的是，我传入的缓冲区的数据量是 32 的倍数，这不会改变结果。

感谢您提供的任何帮助！

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